title: Biochemical and genetic characterization of an auxotroph of Bacillus subtilis altered in the Acyl-CoA:acyl-carrier-protein transacylase.
abstract: We have analyzed a mutation of Bacillus subtilis (bfmB) that results in an acyl-CoA:acyl-carrier-protein transacylase with low affinity for branched acyl-CoA substrates; it maps in the acf-hisH region of the chromosome. The aceA mutation, present in the parent of the bfmB mutant, causes a deficiency in pyruvate dehydrogenase and maps in the pycA-pyrA region. Strains carrying the bfmB mutation synthesize branched-chain fatty acids at a rate sufficient for normal growth only if branched acyl-CoA precursors are present in the medium. They grow well if the medium is supplemented with 0.1 mM 2-methylbutyrate, isobutyrate or isovalerate, or with 1.0 mM isoleucine or valine; leucine does not support growth. Growth supported by valine and isoleucine is inhibited by butyrate and other straight short-chain fatty acids at concentrations (0.1 mM) which do not inhibit growth of the standard strain; the inhibition is prevented by short branched fatty acids which are converted to long-chain fatty acids appearing as activity of B. subtilis is controlled by separate enzymatic sites for the acyl-CoA precursors of branched and straight-chain fatty acids. Whether these sites are contained in one or two enzymes is not known.
mesh_terms: D000105:Acetyl Coenzyme A / Q000235:genetics; D000123:Acetyltransferases / Q000235:genetics*; D000213:Acyl Carrier Protein / Q000235:genetics; D051051:Acyl-Carrier Protein S-Acetyltransferase; D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001426:Bacterial Proteins / Q000302:isolation & purification; D002474:Cell-Free System; D002874:Chromosome Mapping; D005227:Fatty Acids / Q000494:pharmacology; D005838:Genotype; D008055:Lipids / Q000302:isolation & purification; D009154:Mutation
chemical_list: D000213:Acyl Carrier Protein; D001426:Bacterial Proteins; D005227:Fatty Acids; D008055:Lipids; D000105:Acetyl Coenzyme A; D000123:Acetyltransferases; D051051:Acyl-Carrier Protein S-Acetyltransferase